QFN pre-molded leadframe having a solder wettable sidewall on each lead

ABSTRACT

The present disclosure is directed to a leadframe package having solder wettable sidewalls that is formed using a pre-molded leadframe and methods of manufacturing the same. A metal plated leadframe with a plurality of recesses and a plurality of apertures is placed into a top and bottom mold tool. A molding compound is then formed in the plurality of recesses and apertures in the leadframe to form a pre-molded leadframe. A plurality of die and wires are coupled to the pre-molded leadframe and the resulting combination is covered in an encapsulant. Alternatively, a bare leadframe can be processed and the metal layer can be applied after encapsulation. A saw or other cutting means is used for singulation to form leadframe packages. Each resulting leadframe package has a solder wettable sidewall for improving the strength of solder joints between the package and a circuit board.

BACKGROUND

Technical Field

The present disclosure is directed to a leadframe package with a solderwettable sidewall formed using a pre-molded leadframe and methods ofmanufacturing the same.

Description of the Related Art

A typical semiconductor package includes a die coupled to a leadframeand various electrical contacts. The resulting combination is thencovered with an encapsulant to create the package. Lands (also referredto as leads) located on a bottom surface of the package and, in manycases, side surfaces of the package provide electrical connection to acircuit board, such as a printed circuit board (PCB). When coupling thepackage to the PCB, the packages are mounted directly on the surface ofthe PCB using surface mount technology (SMT).

Although SMT allows for smaller packages, it also creates somedisadvantages. In particular, the solder joints between the package andthe PCB can be weakened due to the PCB and the package having differentcoefficients of thermal expansions (CTE). Thus, the reliability of thepackage may in some cases depend on the integrity of the solder jointsand therefore, stronger solder joints are desired. But, most surfacemount leadframes only have solder wettable material on the bottom of thepackage. The sidewalls of the package are often comprised of materialthat is incompatible with solder, which results in weak solder joints,or no solder joints, between the PCB and the sidewalls of the package.Finally, in some cases, the force of manufacturing processes in selectlocations of the thin metal leadframe results in leadframe bouncing,which may cause the thin metal of the leadframe to crack or fracture.

Past responses to these issues have been to add additional elements tothe package. These solutions are often cost-prohibitive because addingadditional elements increases the number of steps in the manufacturingprocess, which decreases efficiency and necessarily increases the perunit manufacturing cost of each package. Further, many solutions preventthe package from being inspected by Automatic Visual Inspection (AVI),which can result in lower package reliability and cycle life because thesolder joints cannot be properly inspected before leaving themanufacturing facility.

These issues are embodied in a typical semiconductor package 20, asshown in FIG. 1. The package 20 has a metal layer 22 on a bottom surfaceof certain portions of the package 20. The package 20 also has sidewalls24 with a first portion 28 comprised of encapsulant and a second portion26 comprised of lead. As such, when the package 20 is attached to a PCBor other circuit board, no solder joints can be formed between the PCBand the sidewalls 24 because both the encapsulant and the lead arecomprised of material that is incompatible with solder. As a result,solder joints cannot be formed between the PCB and the sidewall 24 ofthe package 20, which reduces the strength of the solder joints in thepackage 20 and prevents the package 20 from being inspected by AVI. Thenet outcome is a less reliable package.

BRIEF SUMMARY

Embodiments of the present disclosure are directed to leadframe packageshaving a solder wettable sidewall that are formed using a pre-moldedleadframe and methods of manufacturing the same. In one embodiment, apre-molded leadframe is formed by using a bottom mold tool having aplurality of ridges. A mold release film is placed over a first surfaceof the bottom mold tool and each of the ridges. Then, a leadframe isformed with a plurality of recesses having a size and shape to match theridges and having a plurality of apertures between die pads and theleads of the leadframe. After forming the plurality of apertures andrecesses, a metal layer is formed on the leadframe, such that the metallayer surrounds each die and each lead. The leadframe is then placed onthe bottom mold tool and a top mold tool with a plurality of cavities isplaced on the other side of the leadframe.

With the molds in place, molding compound is formed in the aperturesbetween the die pads of the leadframe and in the cavities of the topmold tool. When the top and bottom mold tools are released, a pre-moldedleadframe remains with molding compound in the plurality of aperturesand on a first surface of the leadframe. The molding compound in thepre-molded leadframe provides additional support to the leadframe abovethe plurality of recesses, which prevents leadframe bouncing duringprocessing and thereby reduces the likelihood of leadframe damage duringincorporation of the leadframe into a package. Once the pre-moldedleadframe is formed, the leadframe is incorporated into a package bycoupling one or more die to each die pad and coupling a plurality ofwires between each die and the metal layer on one or more leads. Then,an encapsulant is formed over the die, the wires and the pre-moldedleadframe. The resulting combination is then separated with a mechanicalblade or other cutting means at the plurality of recesses to formpackages with solder wettable sidewalls.

In another embodiment, a pre-molded leadframe with a plurality ofrecesses on a first surface is incorporated into a leadframe package. Aplurality of die are coupled to the pre-molded leadframe on a secondsurface and a plurality of wires are coupled between each die and one ormore leads. An encapsulant is then used to cover the die, the wires, andthe pre-molded leadframe. Next, a metal layer is formed on the firstsurface of the leadframe, including each of the plurality of recesses. Asaw or other cutting means is then used to separate the resultingcombination at the plurality of recesses. The result is a leadframepackage having a solder wettable sidewall formed using a pre-moldedleadframe.

When a package with solder wettable sidewalls is mounted to a PCB orother circuit board, the solder wettable sidewalls enable strong solderjoints to be formed between the leads of the package and the PCB. Thisalso increases the solder contact area between the package and the PCB,which results in less resistance and a lower thermal load per solderpin. This reduced thermal load allows for a reduction in the number ofpins required to handle the power supply load. If fewer pins arerequired to carry the positive and negative power supplies, then thepackage can be made with fewer pins, saving money. It also allows for anincrease in the number of signal and data pins in the resulting device,if needed.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the drawings, identical reference numbers identify similar elementsor acts unless the context indicates otherwise. The sizes and relativepositions of elements in the drawings are not necessarily drawn toscale.

FIG. 1 is a cross-sectional view of a leadframe package as is known inthe prior art;

FIG. 2 is a cross-sectional view of an exemplary embodiment of apre-molded leadframe;

FIGS. 3A-F are cross-sectional views of various stages of an assemblyprocess of pre-molded leadframe assembly process, such as the pre-moldedleadframe of FIG. 2, in accordance with an exemplary embodiment of thepresent disclosure;

FIG. 4 is a cross-sectional view of an exemplary embodiment of aleadframe package with solder wettable sidewalls formed using apre-molded leadframe; and

FIGS. 5A-E are cross-sectional views of various stages of an assemblyprocess of leadframe packages with solder wettable sidewalls and formedusing a pre-molded leadframe, such as the leadframe package of FIG. 4,in accordance with an exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION

In the following description, certain specific details are set forth inorder to provide a thorough understanding of various embodiments of thedisclosure. However, one skilled in the art will understand that thedisclosure may be practiced without these specific details. In otherinstances, well-known structures associated with electronic componentsand fabrication techniques have not been described in detail to avoidunnecessarily obscuring the descriptions of the embodiments of thepresent disclosure. The drawings are not necessarily drawn to scale andsome features are enlarged to provide a more clear view of particularfeatures.

Unless the context requires otherwise, throughout the specification andclaims that follow, the word “comprise” and variations thereof, such as“comprises” and “comprising,” are to be construed in an open, inclusivesense, that is, as “including, but not limited to.”

The use of ordinals such as first, second and third does not necessarilyimply a ranked sense of order, but rather may only distinguish betweenmultiple instances of an act or structure.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment. Thus, the appearances of the phrases “in one embodiment” or“in an embodiment” in various places throughout this specification arenot necessarily all referring to the same embodiment. Furthermore, theparticular features, structures, or characteristics may be combined inany suitable manner in one or more embodiments.

As used in this specification and the appended claims, the singularforms “a,” “an,” and “the” include plural referents unless the contentclearly dictates otherwise. It should also be noted that the term “or”is generally employed in its sense including “and/or” unless the contentclearly dictates otherwise.

The present disclosure is generally directed to providing a leadframepackage with a solder wettable sidewall that is formed using apre-molded leadframe. An exemplary embodiment of a pre-molded leadframe30 is shown in FIG. 2. In this embodiment, the pre-molded leadframe 30has a first side 32 and a second side 34. The leadframe 30 also has aplurality of die pads 42 and a plurality of leads 44. Each of theplurality of leads 44 comprises a first lead 48 and a second lead 50joined together by a thin section of leadframe 31. A thickness of thesection of leadframe 31 will vary depending on a depth 54 of a pluralityof recesses 33 formed in the second side 34 of the pre-molded leadframe30, as described in more detail below. The depth 54 also comprises acertain percentage of a thickness 52 of the pre-molded leadframe 30. Insome embodiments, the depth 54 is more than 50% of the thickness 52,although other variations may be selected depending on the desiredcharacteristics of the leadframe 30.

The plurality of die pads 42 are separated by a plurality of apertures38. In this embodiment, the plurality of apertures 38 are filled with afirst plurality of molding compound portions 40. A second plurality ofmolding compound portions 46 are placed on the first side 32 of thepre-molded leadframe 30 at a location that is adjacent to the pluralityof recesses 33 that are formed on the second side 34 of the leadframebetween the first lead 48 and the second lead 50 of each of theplurality of leads 44. The plurality of recesses 33 define sidewalls 56that are exposed to an exterior environment. When the pre-moldedleadframe 30 is formed into a package, as described below, the sidewalls56 are covered by a metal layer to create packages with solder wettablesidewalls. In an alternative embodiment, the metal layer is formed oneach of the plurality of die pads 42 and each of the plurality of leads44 prior to forming the first and second plurality of molding compoundportions, as in FIGS. 3C-F.

The first plurality of molding compound portions 40 and the secondplurality of molding compound portions 46 each provide support to thepre-molded leadframe 30 when the leadframe undergoes additionalprocessing. A typical leadframe is a very thin, wide layer of copper orother metal that is likely to crack or fracture during the die and wireattach processes, or during other steps in manufacturing. Usually thisdamage is the result of leadframe bouncing, which occurs after a forceis applied in a certain area of the leadframe and the effects of theforce spread throughout the leadframe, causing the thin material tobounce. The first plurality of molding compound portions 40 and thesecond plurality of molding compound portions 46 provide additionalmaterial in vulnerable locations of the leadframe 30. This increasedarea of material results in lower stresses for the leadframe 30 whensubjected to the same forces inherent in the manufacturing process. As aresult, the likelihood of cracking or fracture is greatly reduced. Thestress is further reduced by the molding compound material itself, whichacts as a buffer to absorb vibrations that occur due to leadframebouncing or other manufacturing induced forces.

An exemplary embodiment of a method of manufacturing the pre-moldedleadframe 30 is shown in FIGS. 3A-F. In the embodiment that begins inFIG. 3A, a bottom mold tool 58 is formed with a plurality of ridges 62on a first surface 60 of the bottom mold tool 58. The bottom mold tool58 is comprised of metal, or another suitable material, and a size and ashape of each of the plurality of ridges 62 can vary according to designpreferences or the particular application for the resulting pre-moldedleadframe. Then, in FIG. 3B, a mold release film 64 is placed over thefirst surface 60 of the bottom mold tool 58, including each of theplurality of ridges 62. The mold release film 64 is non-adhesive andprevents the leadframe from adhering to the bottom mold tool 58 whenmolding compound is formed on the leadframe.

Once the mold release film 64 is in place, a leadframe 29 is placed onthe bottom mold tool 58 and the mold release film 64, as shown in FIG.3C. The leadframe 29 includes a plurality of die pads 42 and a pluralityof leads 44. The plurality of die pads 42 are separated from theplurality of leads 44 by a plurality of apertures 38 that are formed inthe leadframe 29 prior to placement. The plurality of leads 44 areseparated into the first lead 48 and the second lead 50 of each of theplurality of leads 44 by a first plurality of recesses 33. The firstplurality of recesses 33 are formed with a size and a shape configuredto receive the plurality of ridges 62. Each of the plurality ofapertures 38 and the first plurality of recesses 33 may be formed usingwet or dry etching, laser etching, or using a mechanical blade, inaddition to other alternatives. After the plurality of apertures 38 andthe first plurality of recesses 33 are formed in the leadframe 29, ametal layer 82 is positioned on each die pad 42 and each lead 44. Theleadframe 29 is coated in the metal layer 82, such that the metal layer82 is positioned on each surface of each die pad 42 and each lead 44.The metal layer 82 may be comprised of any suitable layer or combinationof layers that form a strong connection with solder, namely a layer thatis wettable to solder. For example, the layer 82 might be tin or analloy of tin. Alternatively, the layer 82 might be a bi-layer of nickeland gold or a tri-layer of nickel, palladium, and gold.

The solder wettable layer 82 can be applied at any one of variousdifferent stages in the process. In the embodiment of FIG. 2, the layer82 is applied after the pre-molded lead frame is fully formed, butbefore the die is attached. Thus, the layer 82 is not shown in FIG. 2,but will be applied as the next step. In the embodiment of FIG. 3C, thelayer 82 is applied to the lead frame before it is placed in the moldfor the first time. In further alternative embodiments, it can beapplied before the die pads and leads of the lead frame are formed andetched or after the etching step. It can also be applied after the dieis attached and after the final encapsulation step.

With the leadframe 29 in place, a top mold tool 66 is placed over theleadframe 29, as in FIG. 3D. The top mold tool 66 has a second pluralityof recesses 68. The second plurality of recesses 68 are positioned abovethe first plurality of recesses 33 such that molding compound can beformed on the leadframe 29. This provides a passage way for the moldingcompound to more completely flow around the lead frame 29 to fill theapertures 38 and also provides additional rigidity and support to thearea of leadframe above the first plurality of recesses 33. If therecess 33 is quite deep, then having the block of molding compounddirectly over each recess will add stiffness and provide better handlingof the lead frame during the manufacturing process. The plurality ofridges 62 provide support for the leadframe during the formation ofmolding compound on the leadframe. Once the top mold tool 66 and thebottom mold tool 58 are secure, the first plurality of molding compoundportions 40 and the second plurality of molding compound portions 46 areformed in the plurality of apertures 38 and the second plurality ofrecesses 68, respectively, as in FIG. 3E. The second plurality ofmolding compound portions 46 contact the metal layer 82 on a surface ofeach lead 44 and the first plurality of molding compound portions 40contact the metal layer on one die pad 42 and one lead 44.

Once the first plurality of molding compound portions 40 and the secondplurality of molding compound portions 46 are formed, the bottom moldtool 58 and the top mold tool 66 are released and the pre-moldedleadframe 30 is removed from the mold tools, as in FIG. 3F. Theresulting pre-molded leadframe 30 has the first plurality of moldingcompound portions 40 and the second plurality of molding compoundportions 46 to protect against the effects of leadframe bouncing whenthe pre-molded leadframe 30 undergoes additional manufacturing to becomeintegrated into a leadframe package. In addition, sidewalls 56 of eachof the first plurality of recesses 33 are covered by the metal layer 82.When the pre-molded leadframe 30 is formed into a leadframe package, thesidewalls are exposed on a portion of a sidewall of the package, and themetal layer 82 on the sidewalls of the package allows for the formationof strong solder joints between sidewalls of the package and the PCB orother board.

An exemplary embodiment of a leadframe package 70 with solder wettablesidewalls that is formed using a pre-molded leadframe is shown in FIG.4. In this embodiment, the leadframe package 70 includes a die 72coupled to a die pad 43 with a tape or other suitable adhesive 71 and aplurality of leads 74 spaced apart from the die pad 43. Each of theplurality of leads 74 includes a first side 78, a second side 80 and asidewall 85. The lead sidewall 85 includes a flange 83 and a leadportion 86. A metal layer 82 extends around each surface of the die pad43 and around the first side 78, the second side 80 and the portion 86of each lead 74. A plurality of wires 76 are coupled between the die 72and the metal layer 82 on one or more of the plurality of leads 74. Themetal layer 82 may be one or more of tin, nickel, palladium, or gold,although other metals or materials may also be useful according to thedesign requirements. The metal layer 82 on the lead portion 86 of thesidewall 85 allows for solder joints to form between a sidewall of thepackage 70 and the PCB or other board. Presence of solder on thesidewall of the package allows for formation of solder joints betweenthe sidewall and the PCB and also allows for inspection by AVI, whichhelps identify flaws and other issues before the package and board leavethe manufacturing or testing facility, which further increasesreliability.

The plurality of leads 74 are spaced apart from the die pad 43 by theplurality of apertures 38. The plurality of apertures 38 are filled withthe first plurality of molding compound portions 40, which may be formedusing the process described above with reference to the pre-moldedleadframe. The leadframe package 70 also includes a portion of one ormore of the second plurality of molding compound portions 46 on thefirst side 78 of the plurality of leads 74.

The die 72, the plurality of wires 76 and the second plurality ofmolding compound portions 46 are encapsulated by an encapsulant 84. Oncethe first plurality of molding compound portions 40 and the secondplurality of molding compound portions 46 are cured through the formingprocess, the application of heat and pressure to form the encapsulant 84will not cause the first and second plurality of molding compoundportions 40, 46 to melt or degrade. In other words, the melting ordegradation temperature of the first and second plurality of moldingcompound portions 40, 46 after curing is below the temperature at whichthe encapsulant 84 is placed.

In the embodiment of FIG. 4, the layer 82 was applied prior to thepre-molded leadframe being formed, similar to the sequence shown in FIG.3C.

In an alternative embodiment, the sidewall 85 is substantially verticaland the lead portion 86 includes the sidewall 85 and the flange 83, asdescribed below. As a result, the entire sidewall 85 is covered by themetal layer 82. A width or height of the flange 83 may vary depending ifa deeper recess is cut into the second side of each of the plurality ofleads, as described above with reference to the pre-molded leadframe.

An exemplary embodiment of a method of manufacturing the leadframepackage 70 with solder wettable sidewalls that is formed using apre-molded leadframe is shown in Figures FIG. 5A-E. The process beginsin FIG. 5A with the pre-molded leadframe 30. The pre-molded leadframe 30has the plurality of die pads 42 and the plurality of leads 44 with eachof the plurality of leads 44 comprising the first lead 48 and the secondlead 50. The pre-molded leadframe 30 further includes the firstplurality of molding compound portions 40 and the second plurality ofmolding compound portions 46, formed according to embodiments of thepresent disclosure. In the embodiment of FIG. 5A, the layer 82 has notyet been formed, but will be formed later.

In FIG. 5B, a plurality of die 72 are coupled to the plurality of diepads 42. The plurality of wires 76 are coupled between each die and oneor more of the plurality of leads 44.

As illustrated in FIG. 5C, the encapsulant 84 is formed over theplurality of die 72, the plurality of wires 76 and the second pluralityof molding compound portions 46. In some embodiments, the encapsulant 84also contacts or covers a surface of the first plurality of moldingcompound portions 40. The array of packages are then removed from themold.

After removal from the mold, the metal layer 82 is formed on any exposedmetal surface of the array. Thus, it will be formed on each of theplurality of die pads 42 and each of the plurality of leads 44,including the sidewall of the leads, as in FIG. 5D. The metal layer 82extends to the plurality of recesses 33 and covers a first side 51 and asecond side 53 of each of the plurality of recesses 33.

After the layer 82 is formed, a mechanical blade or other cutting meansis used to singulate the resulting array to obtain individual packages70, as in FIG. 5E. Each leadframe package 70 has a sidewall 88 with aportion 86 covered by the metal layer 82. This allows for solder jointsto form between the sidewall 88 of the package and the PCB or othercircuit board, resulting in a more reliable package that is inspected byAVI, the advantages of which have already been described.

In an alternative exemplary embodiment, the leadframe package 70 has thelead sidewall 85 without the flange 83 where the metal layer 82 coversthe entire lead sidewall 85. In this embodiment, a tie bar is attachedto a leadframe before processing in order to prevent leadframe bendingor bouncing during processing. Then, the leadframe with the tie-barattached can be cut all the way through at the plurality of recesses 33to form the first lead 48 and the second lead 50 of each of theplurality of leads 44 and a second plurality of apertures between thefirst lead 48 and the second lead 50. The resulting leadframe having thesecond plurality of apertures is placed in the bottom mold tool 58, withthe ridges 62 having a height sufficient to occupy the second pluralityof apertures.

Then, the second plurality of recesses 68 are formed with a depth thatcorresponds to the second plurality of molding compound portions 46having a sufficiently thick cross-section to support the leads 48 and 50during processing. Then, the pre-molding and package formation processescontinues according to the present disclosure until the tie bar isremoved with a trimming machine or other cutting means prior tosingulation of the respective packages. After singulation, the leadframepackage 70 has the lead sidewall 85 that is covered with the metal layer82. This increased contact surface area allows for stronger solderjoints to form between the package 70 and the PCB or other circuitboard, which improves reliability and further reduces resistancecompared to a package with the metal layer 82 on only a portion 86 ofthe sidewall 85.

The various embodiments described above can be combined to providefurther embodiments. All of the U.S. patents, U.S. patent applicationpublications, U.S. patent applications, foreign patents, foreign patentapplications and non-patent publications referred to in thisspecification and/or listed in the Application Data Sheet areincorporated herein by reference, in their entirety. Aspects of theembodiments can be modified, if necessary to employ concepts of thevarious patents, applications and publications to provide yet furtherembodiments.

These and other changes can be made to the embodiments in light of theabove-detailed description. In general, in the following claims, theterms used should not be construed to limit the claims to the specificembodiments disclosed in the specification and the claims, but should beconstrued to include all possible embodiments along with the full scopeof equivalents to which such claims are entitled. Accordingly, theclaims are not limited by the disclosure.

The invention claimed is:
 1. A method comprising: placing a leadframe ona bottom mold tool, the leadframe having a first plurality of recessesand a plurality of apertures, each of the first plurality of recesseshaving a size and a shape configured to receive one of the plurality ofridges, the leadframe also having a plurality of die pads and aplurality of leads; placing a top mold tool on the leadframe, the topmold tool having a second plurality of recesses; forming a firstplurality of molding compound portions in the plurality of apertures andforming a second plurality of molding compound portions in the secondplurality of recesses in a single molding step to form a pre-moldedleadframe; releasing the top mold tool and the bottom mold tool, thereleasing including removing the pre-molded leadframe from the top moldtool and the bottom mold tool; coupling a plurality of dies to eachrespective die pad of the pre-molded leadframe; coupling the pluralityof dies to the plurality of leads through a plurality of wires;encapsulating the plurality of dies, the plurality of wires, and thesecond plurality of molding compound portions with an encapsulant; andcutting the encapsulant, the leadframe and a metal layer to form aplurality of leadframe packages, each leadframe package having a firstsidewall and a second sidewall with a portion of each sidewall coveredby the metal layer.
 2. The method of claim 1 wherein positioning themold release film includes the mold release film comprised of anon-adhesive material.
 3. The method of claim 1 wherein forming thesecond plurality of molding compound portions further comprises formingthe second plurality of molding compound portions at a location adjacentto the first plurality of recesses.
 4. The method of claim 1 whereinforming the first plurality of recesses further comprises removing aremaining portion of the leadframe opposite the first plurality ofrecesses to form a plurality of leads.
 5. The method of claim 4 furthercomprising: forming a plurality of leadframe packages with thepre-molded leadframe, each of the plurality of leadframe packages havinga first lead portion of the first sidewall and a second lead portion ofthe second sidewall; and forming the metal layer on the first leadportion of the first sidewall and the second lead portion of the secondsidewall.
 6. The method of claim 5 wherein forming the metal layer onthe first lead portion and the second lead portion further comprises themetal layer substantially covering the first lead portion of the firstsidewall and the second lead portion of the second sidewall.
 7. Themethod of claim 1 further comprising forming the metal layer on anexposed surface of the leadframe and on the first plurality of recessesin the leadframe is carried out prior to the step of placing theleadframe on the bottom mold tool.
 8. The method of claim 1 furthercomprising forming a metal layer on an exposed surface of the leadframeand on the first plurality of recesses in the leadframe is carried outafter the step of removing the pre-molded leadframe from the top moldtool and prior to the step of and the bottom mold tool placing theleadframe on the bottom mold tool and prior to the step of coupling aplurality of dies to each respective die pad of the pre-moldedleadframe.
 9. The method of claim 1 wherein cutting the encapsulant, theleadframe and the metal layer includes the first sidewall and the secondsidewall each having a lead portion.
 10. The method of claim 1 whereincutting the encapsulant, the leadframe and the metal layer furthercomprises forming a flange, the flange including the lead portion andextending from the first plurality of recesses.
 11. The method of claim1 wherein forming the metal layer further comprises forming a layer thatincludes tin on the leadframe.
 12. The method of claim 1 wherein formingthe metal layer further comprises forming a layer that includes at leasttwo different layers, one on top of each other and the layers include atleast two selected from the group of nickel, palladium, and gold. 13.The method according to claim 1, further including: forming the metallayer on an exposed surface of the leadframe and on the first pluralityof recesses in the leadframe.
 14. The method according to claim 13wherein forming the metal layer on an exposed surface of the leadframeand on the first plurality of recesses in the leadframe occurs afterencapsulating the plurality of dies, the plurality of wires, and thesecond plurality of molding compound portions with an encapsulant andbefore cutting the encapsulant, the leadframe and the metal layer toform a plurality of leadframe packages, each leadframe package having afirst sidewall and a second sidewall with a portion of each sidewallcovered by the metal layer.
 15. The method according to claim 1, furtherincluding: positioning a mold release film on a first surface of abottom mold tool, the mold tool having a plurality of ridges prior toplacing a leadframe on the bottom mold tool.
 16. The method of claim 15wherein positioning a mold release film on a first surface of a bottommold tool prior to placing the leadframe on the bottom mold tool, themold tool having a plurality of ridges, the leadframe having a firstplurality of recesses and a plurality of apertures, each of the firstplurality of recesses having a size and a shape configured to receiveone of the plurality of ridges, the leadframe also having a plurality ofdie pads and a plurality of leads.
 17. A method of molding asemiconductor die comprising: placing a leadframe in a mold; injectingmolding compound into the mold in a top region of the leadframe toadhere to a top of the leadframe; injecting molding compound into themold in a plurality of apertures of the leadframe to adhere to a bottomregion of the leadframe; releasing the leadframe and the moldingcompound from the mold; coupling a plurality of dies to each respectivedie pad of the leadframe; coupling the plurality of dies to theleadframe through a plurality of wires; encapsulating the plurality ofdies, the plurality of wires, and the second plurality of moldingcompound portions with an encapsulant; and cutting the encapsulant, theleadframe and the molding compound to form a plurality of leadframepackages.
 18. The method of claim 17 further including: forming a firstmetal layer on the leadframe prior to placing the leadframe in the mold.19. The method of claim 17 further including: forming a second metallayer on the leadframe after removing it from the mold and aftercoupling a plurality of die to the leadframe and prior to encapsulatingthe plurality of die, the plurality of wires, and the second pluralityof molding compound portions with an encapsulant.